A technique has been proposed in which when a utilization factor of a buffer provided in a relay node between a transmitting device and a receiving device reaches a predetermined value, congestion that occurred in a communication path is solved by decreasing a packet amount transmitted to the receiving device from the transmitting device (for example, refer to Japanese Laid-open Patent Publication No. 9-149077).
A technique has been proposed in which when congestion occurs in a communication path between a transmitting terminal and a receiving terminal, the transmitting terminal is notified of information indicating the congestion and thus, the notified transmitting terminal suppresses the transmission of the packet, thereby solving the congestion (for example, refer to Japanese Laid-open Patent Publication No. 63-024742 and Japanese Laid-open Patent Publication No. 2-170646).
However, since the above described technique is for solving the congestion by detecting the congestion that occurred in the communication path, it is difficult to suppress occurrence of the congestion. For example, in an information processing system such as a parallel computer system in which a plurality of the information processing apparatuses which are coupled to each other via switch devices, the congestion that occurred in one spot widely spreads in a chain reaction. It is preferable to suppress occurrence of the congestion, but a technique for suppressing the occurrence of the congestion has not been proposed.